xref: /openbmc/qemu/hw/net/vhost_net.c (revision bfb27e60) 
1 /*
2  * vhost-net support
3  *
4  * Copyright Red Hat, Inc. 2010
5  *
6  * Authors:
7  *  Michael S. Tsirkin <mst@redhat.com>
8  *
9  * This work is licensed under the terms of the GNU GPL, version 2.  See
10  * the COPYING file in the top-level directory.
11  *
12  * Contributions after 2012-01-13 are licensed under the terms of the
13  * GNU GPL, version 2 or (at your option) any later version.
14  */
15 
16 #include "net/net.h"
17 #include "net/tap.h"
18 #include "net/vhost-user.h"
19 
20 #include "hw/virtio/virtio-net.h"
21 #include "net/vhost_net.h"
22 #include "qemu/error-report.h"
23 
24 #include "config.h"
25 
26 #ifdef CONFIG_VHOST_NET
27 #include <linux/vhost.h>
28 #include <sys/socket.h>
29 #include <linux/kvm.h>
30 #include <fcntl.h>
31 #include <linux/virtio_ring.h>
32 #include <netpacket/packet.h>
33 #include <net/ethernet.h>
34 #include <net/if.h>
35 #include <netinet/in.h>
36 
37 #include <stdio.h>
38 
39 #include "hw/virtio/vhost.h"
40 #include "hw/virtio/virtio-bus.h"
41 
42 struct vhost_net {
43     struct vhost_dev dev;
44     struct vhost_virtqueue vqs[2];
45     int backend;
46     NetClientState *nc;
47 };
48 
49 /* Features supported by host kernel. */
50 static const int kernel_feature_bits[] = {
51     VIRTIO_F_NOTIFY_ON_EMPTY,
52     VIRTIO_RING_F_INDIRECT_DESC,
53     VIRTIO_RING_F_EVENT_IDX,
54     VIRTIO_NET_F_MRG_RXBUF,
55     VHOST_INVALID_FEATURE_BIT
56 };
57 
58 /* Features supported by others. */
59 const int user_feature_bits[] = {
60     VIRTIO_F_NOTIFY_ON_EMPTY,
61     VIRTIO_RING_F_INDIRECT_DESC,
62     VIRTIO_RING_F_EVENT_IDX,
63 
64     VIRTIO_F_ANY_LAYOUT,
65     VIRTIO_NET_F_CSUM,
66     VIRTIO_NET_F_GUEST_CSUM,
67     VIRTIO_NET_F_GSO,
68     VIRTIO_NET_F_GUEST_TSO4,
69     VIRTIO_NET_F_GUEST_TSO6,
70     VIRTIO_NET_F_GUEST_ECN,
71     VIRTIO_NET_F_GUEST_UFO,
72     VIRTIO_NET_F_HOST_TSO4,
73     VIRTIO_NET_F_HOST_TSO6,
74     VIRTIO_NET_F_HOST_ECN,
75     VIRTIO_NET_F_HOST_UFO,
76     VIRTIO_NET_F_MRG_RXBUF,
77     VIRTIO_NET_F_STATUS,
78     VIRTIO_NET_F_CTRL_VQ,
79     VIRTIO_NET_F_CTRL_RX,
80     VIRTIO_NET_F_CTRL_VLAN,
81     VIRTIO_NET_F_CTRL_RX_EXTRA,
82     VIRTIO_NET_F_CTRL_MAC_ADDR,
83     VIRTIO_NET_F_CTRL_GUEST_OFFLOADS,
84 
85     VIRTIO_NET_F_MQ,
86 
87     VHOST_INVALID_FEATURE_BIT
88 };
89 
90 static const int *vhost_net_get_feature_bits(struct vhost_net *net)
91 {
92     const int *feature_bits = 0;
93 
94     switch (net->nc->info->type) {
95     case NET_CLIENT_OPTIONS_KIND_TAP:
96         feature_bits = kernel_feature_bits;
97         break;
98     case NET_CLIENT_OPTIONS_KIND_VHOST_USER:
99         feature_bits = user_feature_bits;
100         break;
101     default:
102         error_report("Feature bits not defined for this type: %d",
103                 net->nc->info->type);
104         break;
105     }
106 
107     return feature_bits;
108 }
109 
110 unsigned vhost_net_get_features(struct vhost_net *net, unsigned features)
111 {
112     return vhost_get_features(&net->dev, vhost_net_get_feature_bits(net),
113             features);
114 }
115 
116 void vhost_net_ack_features(struct vhost_net *net, unsigned features)
117 {
118     net->dev.acked_features = net->dev.backend_features;
119     vhost_ack_features(&net->dev, vhost_net_get_feature_bits(net), features);
120 }
121 
122 static int vhost_net_get_fd(NetClientState *backend)
123 {
124     switch (backend->info->type) {
125     case NET_CLIENT_OPTIONS_KIND_TAP:
126         return tap_get_fd(backend);
127     default:
128         fprintf(stderr, "vhost-net requires tap backend\n");
129         return -EBADFD;
130     }
131 }
132 
133 struct vhost_net *vhost_net_init(VhostNetOptions *options)
134 {
135     int r;
136     bool backend_kernel = options->backend_type == VHOST_BACKEND_TYPE_KERNEL;
137     struct vhost_net *net = g_malloc(sizeof *net);
138 
139     if (!options->net_backend) {
140         fprintf(stderr, "vhost-net requires net backend to be setup\n");
141         goto fail;
142     }
143 
144     if (backend_kernel) {
145         r = vhost_net_get_fd(options->net_backend);
146         if (r < 0) {
147             goto fail;
148         }
149         net->dev.backend_features = qemu_has_vnet_hdr(options->net_backend)
150             ? 0 : (1 << VHOST_NET_F_VIRTIO_NET_HDR);
151         net->backend = r;
152     } else {
153         net->dev.backend_features = 0;
154         net->backend = -1;
155     }
156     net->nc = options->net_backend;
157 
158     net->dev.nvqs = 2;
159     net->dev.vqs = net->vqs;
160 
161     r = vhost_dev_init(&net->dev, options->opaque,
162                        options->backend_type, options->force);
163     if (r < 0) {
164         goto fail;
165     }
166     if (!qemu_has_vnet_hdr_len(options->net_backend,
167                                sizeof(struct virtio_net_hdr_mrg_rxbuf))) {
168         net->dev.features &= ~(1 << VIRTIO_NET_F_MRG_RXBUF);
169     }
170     if (backend_kernel) {
171         if (~net->dev.features & net->dev.backend_features) {
172             fprintf(stderr, "vhost lacks feature mask %" PRIu64
173                    " for backend\n",
174                    (uint64_t)(~net->dev.features & net->dev.backend_features));
175             vhost_dev_cleanup(&net->dev);
176             goto fail;
177         }
178     }
179     /* Set sane init value. Override when guest acks. */
180     vhost_net_ack_features(net, 0);
181     return net;
182 fail:
183     g_free(net);
184     return NULL;
185 }
186 
187 bool vhost_net_query(VHostNetState *net, VirtIODevice *dev)
188 {
189     return vhost_dev_query(&net->dev, dev);
190 }
191 
192 static void vhost_net_set_vq_index(struct vhost_net *net, int vq_index)
193 {
194     net->dev.vq_index = vq_index;
195 }
196 
197 static int vhost_net_start_one(struct vhost_net *net,
198                                VirtIODevice *dev)
199 {
200     struct vhost_vring_file file = { };
201     int r;
202 
203     net->dev.nvqs = 2;
204     net->dev.vqs = net->vqs;
205 
206     r = vhost_dev_enable_notifiers(&net->dev, dev);
207     if (r < 0) {
208         goto fail_notifiers;
209     }
210 
211     r = vhost_dev_start(&net->dev, dev);
212     if (r < 0) {
213         goto fail_start;
214     }
215 
216     if (net->nc->info->poll) {
217         net->nc->info->poll(net->nc, false);
218     }
219 
220     if (net->nc->info->type == NET_CLIENT_OPTIONS_KIND_TAP) {
221         qemu_set_fd_handler(net->backend, NULL, NULL, NULL);
222         file.fd = net->backend;
223         for (file.index = 0; file.index < net->dev.nvqs; ++file.index) {
224             const VhostOps *vhost_ops = net->dev.vhost_ops;
225             r = vhost_ops->vhost_call(&net->dev, VHOST_NET_SET_BACKEND,
226                                       &file);
227             if (r < 0) {
228                 r = -errno;
229                 goto fail;
230             }
231         }
232     }
233     return 0;
234 fail:
235     file.fd = -1;
236     if (net->nc->info->type == NET_CLIENT_OPTIONS_KIND_TAP) {
237         while (file.index-- > 0) {
238             const VhostOps *vhost_ops = net->dev.vhost_ops;
239             int r = vhost_ops->vhost_call(&net->dev, VHOST_NET_SET_BACKEND,
240                                           &file);
241             assert(r >= 0);
242         }
243     }
244     if (net->nc->info->poll) {
245         net->nc->info->poll(net->nc, true);
246     }
247     vhost_dev_stop(&net->dev, dev);
248 fail_start:
249     vhost_dev_disable_notifiers(&net->dev, dev);
250 fail_notifiers:
251     return r;
252 }
253 
254 static void vhost_net_stop_one(struct vhost_net *net,
255                                VirtIODevice *dev)
256 {
257     struct vhost_vring_file file = { .fd = -1 };
258 
259     if (net->nc->info->type == NET_CLIENT_OPTIONS_KIND_TAP) {
260         for (file.index = 0; file.index < net->dev.nvqs; ++file.index) {
261             const VhostOps *vhost_ops = net->dev.vhost_ops;
262             int r = vhost_ops->vhost_call(&net->dev, VHOST_NET_SET_BACKEND,
263                                           &file);
264             assert(r >= 0);
265         }
266     }
267     if (net->nc->info->poll) {
268         net->nc->info->poll(net->nc, true);
269     }
270     vhost_dev_stop(&net->dev, dev);
271     vhost_dev_disable_notifiers(&net->dev, dev);
272 }
273 
274 static bool vhost_net_device_endian_ok(VirtIODevice *vdev)
275 {
276 #ifdef TARGET_IS_BIENDIAN
277 #ifdef HOST_WORDS_BIGENDIAN
278     return virtio_is_big_endian(vdev);
279 #else
280     return !virtio_is_big_endian(vdev);
281 #endif
282 #else
283     return true;
284 #endif
285 }
286 
287 int vhost_net_start(VirtIODevice *dev, NetClientState *ncs,
288                     int total_queues)
289 {
290     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(dev)));
291     VirtioBusState *vbus = VIRTIO_BUS(qbus);
292     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(vbus);
293     int r, e, i;
294 
295     if (!vhost_net_device_endian_ok(dev)) {
296         error_report("vhost-net does not support cross-endian");
297         r = -ENOSYS;
298         goto err;
299     }
300 
301     if (!k->set_guest_notifiers) {
302         error_report("binding does not support guest notifiers");
303         r = -ENOSYS;
304         goto err;
305     }
306 
307     for (i = 0; i < total_queues; i++) {
308         vhost_net_set_vq_index(get_vhost_net(ncs[i].peer), i * 2);
309     }
310 
311     r = k->set_guest_notifiers(qbus->parent, total_queues * 2, true);
312     if (r < 0) {
313         error_report("Error binding guest notifier: %d", -r);
314         goto err;
315     }
316 
317     for (i = 0; i < total_queues; i++) {
318         r = vhost_net_start_one(get_vhost_net(ncs[i].peer), dev);
319 
320         if (r < 0) {
321             goto err_start;
322         }
323     }
324 
325     return 0;
326 
327 err_start:
328     while (--i >= 0) {
329         vhost_net_stop_one(get_vhost_net(ncs[i].peer), dev);
330     }
331     e = k->set_guest_notifiers(qbus->parent, total_queues * 2, false);
332     if (e < 0) {
333         fprintf(stderr, "vhost guest notifier cleanup failed: %d\n", e);
334         fflush(stderr);
335     }
336 err:
337     return r;
338 }
339 
340 void vhost_net_stop(VirtIODevice *dev, NetClientState *ncs,
341                     int total_queues)
342 {
343     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(dev)));
344     VirtioBusState *vbus = VIRTIO_BUS(qbus);
345     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(vbus);
346     int i, r;
347 
348     for (i = 0; i < total_queues; i++) {
349         vhost_net_stop_one(get_vhost_net(ncs[i].peer), dev);
350     }
351 
352     r = k->set_guest_notifiers(qbus->parent, total_queues * 2, false);
353     if (r < 0) {
354         fprintf(stderr, "vhost guest notifier cleanup failed: %d\n", r);
355         fflush(stderr);
356     }
357     assert(r >= 0);
358 }
359 
360 void vhost_net_cleanup(struct vhost_net *net)
361 {
362     vhost_dev_cleanup(&net->dev);
363     g_free(net);
364 }
365 
366 bool vhost_net_virtqueue_pending(VHostNetState *net, int idx)
367 {
368     return vhost_virtqueue_pending(&net->dev, idx);
369 }
370 
371 void vhost_net_virtqueue_mask(VHostNetState *net, VirtIODevice *dev,
372                               int idx, bool mask)
373 {
374     vhost_virtqueue_mask(&net->dev, dev, idx, mask);
375 }
376 
377 VHostNetState *get_vhost_net(NetClientState *nc)
378 {
379     VHostNetState *vhost_net = 0;
380 
381     if (!nc) {
382         return 0;
383     }
384 
385     switch (nc->info->type) {
386     case NET_CLIENT_OPTIONS_KIND_TAP:
387         vhost_net = tap_get_vhost_net(nc);
388         break;
389     case NET_CLIENT_OPTIONS_KIND_VHOST_USER:
390         vhost_net = vhost_user_get_vhost_net(nc);
391         break;
392     default:
393         break;
394     }
395 
396     return vhost_net;
397 }
398 #else
399 struct vhost_net *vhost_net_init(VhostNetOptions *options)
400 {
401     error_report("vhost-net support is not compiled in");
402     return NULL;
403 }
404 
405 bool vhost_net_query(VHostNetState *net, VirtIODevice *dev)
406 {
407     return false;
408 }
409 
410 int vhost_net_start(VirtIODevice *dev,
411                     NetClientState *ncs,
412                     int total_queues)
413 {
414     return -ENOSYS;
415 }
416 void vhost_net_stop(VirtIODevice *dev,
417                     NetClientState *ncs,
418                     int total_queues)
419 {
420 }
421 
422 void vhost_net_cleanup(struct vhost_net *net)
423 {
424 }
425 
426 unsigned vhost_net_get_features(struct vhost_net *net, unsigned features)
427 {
428     return features;
429 }
430 void vhost_net_ack_features(struct vhost_net *net, unsigned features)
431 {
432 }
433 
434 bool vhost_net_virtqueue_pending(VHostNetState *net, int idx)
435 {
436     return false;
437 }
438 
439 void vhost_net_virtqueue_mask(VHostNetState *net, VirtIODevice *dev,
440                               int idx, bool mask)
441 {
442 }
443 
444 VHostNetState *get_vhost_net(NetClientState *nc)
445 {
446     return 0;
447 }
448 #endif
449